Sorry if I ask this question again, but I asked it the Astroberry section and haven't got any answer. I think it's better to asked it here in the Mount section. And I have more information now.

The problem I have is that I'm trying to take photos of the comet C/2022 E3 ZTF and now in January/February it's moving fast. I want to take many longer exposures and need to have the mount track with a Custom Tracking Rate.

First, from the CdC I get the comet's relative speed, but it's in hour and I need arcsec/sec for INDI EQMOD driver.

On my homepage I have done a angle format calculator:

www.astrofriend.eu/astronomy/astronomy-c...gle-conversions.html

Which deliver this setting for the comet's speed in arcsec/sec at January 31st which I think is correct calculated.



I take these figures and setup the INDI for Custom Track Rates, dRA and dDEC. But I get a warning that these figures are out of range and it don't accept it.



The warning say I set the dDEC to 0.01 x sideral (15), that's is 0.15 arcsec/sec. According to the limits, 0.05 to 800 x sidereal ( 0.05x15= 0.75 and 800 x 15 = 12000 ) so of course it's out of range. Still I have put in a really high relative speed of the comet.

With these range limitations it's impossible to correct for comet's relative speed. Isn't the Custom Track Rate meant to this purpose, to follow comets and asteroids ?

To me it looks that INDI shouldn't multiply the limits ( 0.05 to 800 ) with the sidereal rate (15) to get this to working. Or am I wrong ?

More realistic have been a range of:
dRA, from 15 +/- 0.01 arcsec/sec to 15 +/-800 arcsec/sec.
dDEC, from +/- 0.01 arcsec/sec to +/-800 arcsec/sec.

1' / hour is 0.017 arsec/sec. When making a movie the comet can be followed for many hours.

Not many days until the comet ZTF is at its closets position, stressed

/Lars

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